torr

Convert to and from torrs to other major units of pressure

A unit of atmospheric pressure, = exactly ¹⁄₇₆₀ atmosphere = exactly ^101,325⁄₇₆₀ pascals or approximately 133.322 368 pascals. Symbol, Torr.

It is named for the Italian physicist Evangelista Torricelli (1608 – 1647).

To within 1 part per million, 1 torr is equal to the pressure of a column of mercury 1 millimeter high at Earth's surface. See conventional millimeter of mercury.

According to the current national standard in the United States¹, the torr is not to be used. The pascal should be used instead.

1. IEEE/ASTM SI 10™-2002.
American National Standard for Use of the International System of Units (SI): The Modern Metric System.
New York: IEEE, 30 December 2002.

See Section 3.3.3.